Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Extremely cold molecules created by Sandia and Columbia University researchers

15.12.2003


Dave Chandler aligns mirrors used to direct laser beams into an apparatus that generates very cold molecules and measures their velocity.
Credit: Sandia Corporation


Colors of the ball indicate the number of molecules at a given velocity. The bright spot at the top of the image represents molecules moving with less than 15 M/Sec, with the intensity of the spot proportional to the number moving that slowly. The density of slow molecules is approximately 108 molecules per cm3.
Credit: Sandia Corporation


Using a method usually more suitable to billiards than atomic physics, researchers from Sandia National Laboratories and Columbia University have created extremely cold molecules that could be used as the first step in creating Bose-Einstein molecular condensates. The work is published in the Dec. 12 Science.

The serendipitous achievement came when researchers at Sandia’s Livermore, Calif., and Columbia University, studying collisional energy transfer between a beam of atoms intersecting a beam of molecules, noted that a certain number of collisions occurred -- as they might between two billiard balls -- at exactly the right velocity for molecules to become motionless.

A motionless molecule is a cold molecule, according to laws of physics.



The study had led to a new technique for cooling molecules to millikelvin (a thousandth of a degree Kelvin above absolute zero) temperatures -- a first crucial step toward molecular ultra-coldness.

Though they were experts in neither cold molecules nor cold atoms, the researchers knew that atoms cooled to the nanokelvin (a billionth of a degree Kelvin) temperature range had been achieved several years ago with interesting basic-science results.

One product of the study of cold atoms is a new state of matter called a Bose-Einstein condensate. Certain atoms, bosons, can condense at a very low temperature and act as a single atom -- a fact which some researchers claim may lead to as many new developments as the first laser, originally only a scientific curiousity.

"Our technique has promise to be developed into a first step in the cooling process needed for a molecular Bose-Einstein condensate," says Sandia researcher and principal investigator Dave Chandler. The work is co-authored by Sandia post-doc Mike Elioff and James Valentini of Columbia University.

Very cold atoms and molecules may one day be used as individual yes/no switches (called Q-bits) in computers whose power our present-day imaginations are only beginning to grasp as well as precision gravity detectors that could perhaps locate underground caverns, says Chandler.

The main method used to achieve atomic ultra-cooling to the microkelvin temperature range -- the same preliminary cooling range as the Sandia technique -- makes use of laser beams that intersect at a point. An atom, possessing the appropriate absorption characteristics, passing through that point in effect stands still, like a kid in a dodge-ball game struck from all sides with balls. Transfixed by pressure from the beams, the atom becomes almost motionless.

The problem in cooling molecules by the laser method is that while some atoms possess characteristics that can be harmonically matched by a laser frequency, like the same note played by two pianos, molecular energy frequencies are more complex. This complexity makes them unsuitable for this type of laser cooling.

This leaves the field open for other techniques to be developed for the preliminary cooling of molecules. There have been four or five other techniques, published recently, that have had some level of success at cooling molecules. The most successful method to date has been the welding of ultracold atoms together to make ultracold molecules.

"Our atomic/molecular beam intersection method is inefficient, it’s true," says Chandler. "We only manage to cool one molecule in a million. But -- inefficient or efficient -- we generate cold molecules. With some improvements, we hope to be able to make substantial numbers of cold molecules."

Molecules are cheap, he says, so getting one in a million (1 in 106) cooling collisions out of the 1015 total collisions per second the molecules undergo in the beams doesn’t bother him.

This first-step method -- the only one to rely solely on the masses of the atoms and molecules involved -- could be useful in slowing down the speed of a variety of molecules sufficiently such that magnetic or electrical traps can be used to cool molecules further. Without prior slow-down, molecules would escape these relatively weak traps, like molecules of water rising from the surface of the hot coffee. Cold coffee evaporates fewer molecules.

Instruments in Chandler’s lab, working at their resolution limit, show selected molecules in the intersecting beams slowing from 600 meters/sec to 15 meters/sec. The group’s calculations indicate the speed to be on the order of 4 meters/sec. This average speed for the molecules is equivalent to a temperature on the tens of milliKelvin level -- that is, several thousandths of a degree above the universe’s absolute zero of -273 Celsius.

The last ninety nine yards, so to speak, are the hardest: Bose-Einstein condensates exist in the nanokelvin range, six orders of magnitude colder.


The basic-science work, funded by DOE’s Basic Energy Sciences, focuses on understanding how energy flows between molecules for a better understanding of heat transfer.


Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.

Sandia media contact:
Neal Singer, nsinger@sandia.gov, 505-845-7078

Neal Singer | Sandia Corporation
Further information:
http://www.sandia.gov/news-center/news-releases/2003/physics-astron/cold.html
http://www.sandia.gov

More articles from Physics and Astronomy:

nachricht Argonne and CERN weigh in on the origin of heavy elements
31.03.2020 | DOE/Argonne National Laboratory

nachricht Physicist from Hannover Develops New Photon Source for Tap-proof Communication
30.03.2020 | Leibniz Universität Hannover

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Physicist from Hannover Develops New Photon Source for Tap-proof Communication

An international team with the participation of Prof. Dr. Michael Kues from the Cluster of Excellence PhoenixD at Leibniz University Hannover has developed a new method for generating quantum-entangled photons in a spectral range of light that was previously inaccessible. The discovery can make the encryption of satellite-based communications much more secure in the future.

A 15-member research team from the UK, Germany and Japan has developed a new method for generating and detecting quantum-entangled photons at a wavelength of...

Im Focus: Junior scientists at the University of Rostock invent a funnel for light

Together with their colleagues from the University of Würzburg, physicists from the group of Professor Alexander Szameit at the University of Rostock have devised a “funnel” for photons. Their discovery was recently published in the renowned journal Science and holds great promise for novel ultra-sensitive detectors as well as innovative applications in telecommunications and information processing.

The quantum-optical properties of light and its interaction with matter has fascinated the Rostock professor Alexander Szameit since College.

Im Focus: Stem Cells and Nerves Interact in Tissue Regeneration and Cancer Progression

Researchers at the University of Zurich show that different stem cell populations are innervated in distinct ways. Innervation may therefore be crucial for proper tissue regeneration. They also demonstrate that cancer stem cells likewise establish contacts with nerves. Targeting tumour innervation could thus lead to new cancer therapies.

Stem cells can generate a variety of specific tissues and are increasingly used for clinical applications such as the replacement of bone or cartilage....

Im Focus: Artificial solid fog material creates pleasant laser light

An international research team led by Kiel University develops an extremely porous material made of "white graphene" for new laser light applications

With a porosity of 99.99 %, it consists practically only of air, making it one of the lightest materials in the world: Aerobornitride is the name of the...

Im Focus: Cross-technology communication in the Internet of Things significantly simplified

Researchers at Graz University of Technology have developed a framework by which wireless devices with different radio technologies will be able to communicate directly with each other.

Whether networked vehicles that warn of traffic jams in real time, household appliances that can be operated remotely, "wearables" that monitor physical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“4th Hybrid Materials and Structures 2020” takes place over the internet

26.03.2020 | Event News

Most significant international Learning Analytics conference will take place – fully online

23.03.2020 | Event News

MOC2020: Fraunhofer IOF organises international micro-optics conference in Jena

03.03.2020 | Event News

 
Latest News

Phage capsid against influenza: Perfectly fitting inhibitor prevents viral infection

31.03.2020 | Life Sciences

A 'cardiac patch with bioink' developed to repair heart

31.03.2020 | Life Sciences

Artificial intelligence can speed up the detection of stroke

31.03.2020 | Medical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>